So United fans will be pained to hear for the first time that Sir Alex Ferguson would have stayed on as the most successful manager in English football history, but for the death of his wife Cathy’s twin sister, Bridget Robertson, which persuaded him to retire to be by her side.

Sir Alex Ferguson felt he owed a debt to his wife

Bridget died in October 2012 and Ferguson felt he owed a debt to his wife, who he married in 1966 after falling for her at a “strike meeting” in Glasgow. In his autobiography, Sir Alex revealed: “She always waited up for me. Even if I came through the door at two or three in the morning, Cathy would be there to greet me.” He dedicated that book (which, to declare an interest, I co-wrote), to “Bridget – Cathy’s sister, rock and best friend.”

The bereavement was mentioned as a catalyst at the time, but only now can he admit that he would not have gone when he did, without his need to put Cathy “first.”

Many will be touched to learn Ferguson put his wife’s needs ahead of his own ambitions after 39 years in management; while also wishing things had turned out differently. ‘Fergie’ had become shorthand for success and longevity. Since he abdicated after winning the last of 13 Premier League titles in May 2013, Manchester United have struggled to find a new identity - with his successor, David Moyes lasting less than a year and the Dutchman Louis van Gaal so far failing to convince supporters he is up to the job.

We talk at his home in Cheshire shortly before he leaves to attend the funeral of Neville Neville, father of former United players Gary and Phil. When fans see him climb from his car, from across the street, they shout: “Thank you, Sir Alex,” in tones so grateful he might just have given them the gift of eternal life.

Life after Old Trafford

“Once I made my decision I wasn’t going to go into it as a grumpy old man leaving his job. My dad left the shipyards at 65 because you had to leave your job at 65. The challenges in front of me were good ones, especially the Harvard thing [he teaches part-time at the Harvard Business School]. Then my involvement with United as a director, as an ambassador, and my jobs with Uefa, Unicef. I’ve travelled a bit and I love watching the team.”

Sir Alex Ferguson addresses students at the Harvard Business School Photo: Anita Elberse/HBS

Leading was written with Michael Moritz, chairman of Sequoia Capital, the private investment firm that “helped shape and organise” such corporate giants as Apple, Cisco Systems, Google, PayPal and YouTube. Moritz, who was drawn to Ferguson’s long record of success, writes in an epilogue: “Not many Silicon Valley CEOs, perhaps because many of them are so young, can modulate their tones with comparable dexterity. Sir Alex could simultaneously play cheerleader, motivational speaker, shrink, confessor, piano-tuner, puppet master, choreographer, teacher, judge and lord high executioner.”

The man himself argues that “your personality, your energy, your decision-making, your observation, your communication,” are all part of the mix. “All these things apply to the guy walking into a cable company or Barclays Bank. You’re dealing with human beings, and human beings need to be directed, inspired. They need to have a trust in their boss.”

Football ... b----- hell!

The book covers the whole gamut of management, but what shines brightest is Ferguson’s capacity for continuous rebuilding, his aptitude for handling mavericks and his gift for control.

Secret of his success

“I was never afraid to try things. I was always prepared to risk in terms of winning a game of football. Also, my convictions about young people were always there. I really believe in young people. I’ve always believed in that, producing the young players I did at Aberdeen or St Mirren. Then to Manchester United, where I tried to create what I saw laid down by Matt Busby way back in the 1950s; because that, without doubt, is a true reflection of Manchester United – how it’s developed young players for half a century.”

The firebrand we saw on the touchline at United for two and half decades concealed a multi-layered personality, forged in the shipyards of Govan and then tempered by a tough managerial apprenticeship in Scotland before the move south to United. Throughout there was a need to impose his restless personality on events.

“My trade union background helped a wee bit,” he says. “You’re trying to help people who are less fortunate. For instance the apprentices’ strike – I had no need to go on strike, or encourage the apprentices to go on strike. We [the toolmakers] were well paid. But there were some people who were married with kids and getting paid tuppence.

Ferguson and the six most successful graduates from the Class of 92

“I got my coaching badges by the time I was 24. So when I became a manager at 32 years of age – which was young – I was ready. I had my badges, I had played the game, I think I could make a decision. Thereafter in an industry like that you have to learn or you don’t survive.”

As a player, Ferguson owned pubs in Glasgow: “It’s a hard business. You’re fed up getting knocked in the head too many times on a Saturday night. So when I got the chance to be a manager I said – I’m going to win here, I’m going to be successful. The fear of failure comes into that. Where was I going to go after that? Back to the pub? No way.”

Cast into a world of mediocre players and minuscule budgets, he was drawn to people who reflected his own abrasive and indomitable nature. “It was at Aberdeen where I realised the strong characters in the dressing room were the backbone for the young players.” Manchester United have seen plenty of these warriors down the years and Ferguson mentions several: Bryan Robson, Brian McClair, Mark Hughes, Steve Bruce, Paul Ince, Roy Keane. His definition of a leader is clear: “A strong character can deal with issues they don’t enjoy. They do something about it. They have a determination about them, a purpose about them. They’re winners. Simply that.”

Ferguson won a second Champions League in 2008

A working-class background wasn’t obligatory but often helped: “When you see guys walking at five or six every morning to a pit shaft, to go down to the bowels of the earth, you have to say it must do something for them. It develops a character that people of that ilk would be proud of. In miners’ rows the doors would be always open. In shipbuilding they would all walk to work together and come home together.”

The later years of management

In his later years in management, though, Ferguson found himself dealing with multi-millionaire players and global celebrities who might have resisted his autocratic style. David Beckham was another of those instrumental to United’s long winning run, until his growing fame caused friction between player and manager. Ferguson sold him to Real Madrid in 2003, but the two are now on friendly terms again, after Ferguson forced himself to move with the times.

“You have to embrace it. Dealing with an ego doesn’t bother me. You used to see [Cristiano] Ronaldo standing in front of the mirror loving himself. But it was a nice vanity. The players used to throw jockstraps, boots and all sorts at him. It never bothered him one bit.

“They need to win, these guys: the ones that are cultivating their egos a little bit. You might see a player in a Ferrari and think – what’s he driving that for? But he has to live with that. He’s not going to be driving into town when he’s bottom of the league, or he’s been dropped. Some people can’t judge that. True players can.”

With his 13th, and last, Premier League title

Eric Cantona, enfant terrible-turned-thespian, was another who prospered under Ferguson’s leadership, which mixed romanticism with an iron rod. He says: “I spoke to Cantona every day. He was a very under-rated man and an interesting man. He needed the encouragement that he was at the right club. And he was at the right club. On the training ground you never got one ounce of difficulty with Cantona. Sometimes he would come in for training with his eyebrows down and you would say – what’s wrong with him today? Once he got warmed up, into training, he was fine.

"Ronaldo was another one: a great, great kid. He’s just a serious professional.”

Ferguson’s first principle of management is trust. Both ways. “What you have to do in management is give your trust to them, without any payback. You have to get to a situation where they’re comfortable playing for you and where, when the chips are down, you’re going to be there for them.

“You have to sell yourself to them: ‘Look, I’m here for one reason. To help you be the best you can possibly be. To be the best human being you can possibly be. To make the most money you can possibly make.’ I think I did that quite well at Manchester United. They were my players. They made me successful. I owed them all that loyalty.”

Sir Alex Ferguson with Cristiano Ronaldo, who had a 'nice vanity'

The 'hairdryer' treatment

The eruptions, he maintains, were necessary but calibrated. The ‘hairdryer’ blast. “I had to carry that stupid name about me for a long time. But my teams never played with fear. Not one of them ever played with fear. They expressed themselves and enjoyed playing. They were always adventurous, had a go. That’s the answer. There’s nothing wrong with losing your temper for the right reasons. To make them aware: we are Manchester United. We cannot afford any more of this nonsense.

“We always used to say: nobody comes to your door and gives you money. You have to go out of the door and earn everything. You have to go on the football field and win to achieve and earn your money.”

Like Moritz, Ferguson had a nose for stagnation; for success unravelling. He tells me: “You have to have a mindset – yesterday’s gone. Tomorrow’s another day. What I used to say to a lot of them was: how many medals have you got? Have you got the same number as [Ryan] Giggs? How many have 10 medals? How many have nine medals? When you get to nine, 10 medals, you know you’ve made it at this club.”

Retirement has made him wish he had learned how to “communicate upwards” to owners, chairmen and chief executives. “What I should have learnt earlier was to get rid of that ‘I can rule the world type of attitude’ I had. ‘I can do this myself. I don’t need you.’ I was wrong. The value of communication never stops. Recognising your groundsman and the staff in the laundry, the tea room; there’s a value in terms of creating a fort round about you.”

Team talks were never verbose but always pithy, resonant, in the manner of other great Scottish managers: Busby, Jock Stein and Bill Shankly. “Brief,” he says, summing up his oratory. “Get to the point. Get the bloody job done.”